Treatment of bulky, refractory cancers using adoptive transfer of tumor infiltrating lymphocytes (TILs) represents a powerful approach to therapy for patients with poor prognoses. Gattinoni, et al., Nat. Rev. Immunol. 2006, 6, 383-393. A large number of TILs are required for successful immunotherapy, and a robust and reliable process is needed for commercialization. This has been a challenge to achieve because of technical, logistical, and regulatory issues with cell expansion. IL-2-based TIL expansion followed by a “rapid expansion process” (REP) has become a preferred method for TIL expansion because of its speed and efficiency. Dudley, et al., Science 2002, 298, 850-54; Dudley, et al., J. Clin. Oncol. 2005, 23, 2346-57; Dudley, et al., J. Clin. Oncol. 2008, 26, 5233-39; Riddell, et al., Science 1992, 257, 238-41; Dudley, et al., J. Immunother. 2003, 26, 332-42. REP can result in a 1,000-fold expansion of TILs over a 14-day period, although it requires a large excess (e.g., 200-fold) of irradiated allogeneic peripheral blood mononuclear cells (PBMCs, also known as mononuclear cells (MNCs)), often from multiple donors, as feeder cells, as well as anti-CD3 antibody (OKT3) and high doses of IL-2. Dudley, et al., J. Immunother. 2003, 26, 332-42. TILs that have undergone an REP procedure have produced successful adoptive cell therapy following host immunosuppression in patients with melanoma. Current infusion acceptance parameters rely on readouts of the composition of TILs (e.g., CD28, CD8, or CD4 positivity) and on fold expansion and viability of the REP product.
Current TIL manufacturing processes are limited by length, cost, sterility concerns, and other factors described herein such that the potential to commercialize such processes is severely limited, and for these and other reasons, at the present time no commercial process has become available. There is an urgent need to provide TIL manufacturing processes and therapies based on such processes that are appropriate for commercial scale manufacturing and regulatory approval for use in human patients at multiple clinical centers.